/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Sampling/MeshBakerCommon.h
Compute interpolated Normal value inside triangle using barycentric coordinates
true if a valid normal was returned, false otherwise
bool TriBaryInterpolateNormal ( const void * Mesh, const int32 TriId, const FVector3d & BaryCoords, FVector3f & NormalOut ) const